Aquaculture of redclaw crayfish, Cherax quadricarinatus, is rapidly developing in tropical and sub-tropical regions of the world. As the industry is still in its infancy, grow out diets are generally not formulated specifically for this species as there is limited data on nutrient requirements and the acceptability of various ingredients. Given the recent increases in the price of fish meal (FM), the use of alternative protein sources such as poultry by-product meal (PBM) may be more cost effective. The present research evaluated the response of juvenile redclaw to practical diets utilizing PBM as a replacement for FM. Juvenile redclaw crayfish (0.45 g ± 0.01) were stocked into 24, 600-L, outdoor round tanks at a density of 12.5 m−2. Tanks were supplied water from a watershed reservoir and maintained on a flow through regime. Crayfish in four replicate tanks were maintained on one of the six diets formulated to contain 260 g kg−1 crude protein and 70 g kg−1 crude fat which had previously demonstrated good growth under similar conditions. FM in the basal diets was replaced with PBM at various levels, on an iso-nitrogenous basis, so that the diets contained 150, 120, 90, 60, 30 and 0 g FM kg−1 diet and 78, 105, 132, 158, 185 and 212 g PBM kg−1 diet, respectively. At the conclusion of the 56-day growth trial, survival (>83&percnt;) and growth (>11.3 g or 2400&percnt;) of the crayfish were not significantly different among treatments. Based on these results, PBM appears to be a viable candidate as a replacement for FM in redclaw crayfish diets. NO From Ontario Scholars Portal (blackwell_03102008)